Agilent Technologies L4400 manual 150

7Microwave Switch/Attenuator Driver

Switch state is stored in the instrument. In contrast, the ROUTe:OPEN? and ROUTe:CLOSe queries always check the actual hardware state of the switch for verified channels.

For paired operations on the L4445A (using the ROUTe:CHANnel:DRIVe:PAIRed:MODE command), when you enable verification on either paired channel verification will be enabled on both channels. In addition, the module checks for complementary position indicators on the lower and upper channels of the pair (i.e., the position indicators should indicate opposite states). If the state of the lower and upper position indicators are found to be in the same state (due to a hardware issue), an error is generated and the state of the lower channel is assumed.

When the paired mode is disabled and pulsed mode is enabled, you cannot query the open/closed state of the associated channels unless verification is enabled. While in this mode (single drive operation), only “close” operations are allowed on the channels (“open” operations are not allowed). In this mode, a close operation provides a single pulse on the specified channel.

If you enable verification on a non- paired (single drive), non- pulsed (continuous drive) channel on the L4445A, the ROUTe:CLOSe? and ROUTe:OPEN? commands return the state of the verified device, rather than the drive state of the specified channel. It is possible to have such a channel being driven via a ROUTe:CLOSe command by the channel position indicators show the channel as open. In these cases, use the ROUTe:CHANnel:VERify:POSition:STATe? command to determine exactly which channels are currently being driven.

The ROUTe:CHANnel:VERify:POLarity command sets the logic polarity of the verification lines on specific channels. You can specify the polarity as NORMal (active high) or INVerted (active low).

If you have not enabled verification, you can still query the indicator state of a specific channel using the ROUTe:CHANnel:VERify:POSition:STATe? command. This command is useful for channels on which verification is disabled for activities such as debugging or when verification is disabled for performance reasons.

150 L4400 User’s Guide